Gear-lapping machine



Feb. 21, 1939.y A, E.. T HRUN 2,147,864

GEAR LAPPNG MACHINE Filed Dec. 25, 1956 2 Sheets-Sheet l ATTORNEY.

Feb. 21, 1939. A l yA. E, THF-QUN 2,147,864y

GEAR LAPPING MACHINE Filed Dec. 25,-193e 2 sheets-sheet 2 ATTORNEY.

Patented Feb. 21, 1939 PATENT OFFICE GEAR-Larme MACHINE August E. Timm, Detroit, Mich.; n. John Voigt administrator of August E. Thrun, deceased Application December 23, 1936, Serial No'. 117,276

4 Claims.

My invention pertains to a lapping machine for lapping gears and more particularly to a.

double acting friction controlled gear lapping portions on one side of .each tooth of the lapped gear.

It is a further object of my invention to provide a lapping machine comprising parallel shafts for rotatably supporting lapping gears in lappingr engagement with a gear to be lapped and means tending to drive one lapping gear faster and the other lapping gear slower than the lapped gear through frictional means for applying a smooth continuous pressure to uniformly lap both sides of the teeth of the lapped gear. i

The invention itself, however, both as toits organization and its method of operation together with additional objects and advantages thereof, will best be understood from the following description of specic embodiments, when read in conjunction with the accompanying drawings, in which:

Fig. l is a plan view showing a gear lapping machine constructed in accordance with my invention;

Fig. 2 isa side elevational View showing the side of the machine with the lapped gear and the associated lapping gears, the base being broken away;

Fig. 3 is a diagrammatic view for illustrating the cooperative engaging relation of the lapped gear with the lapping gears for simultaneously lapping opposite sides of the gear teeth; and

Figs. land 5 are sectional views taken along lines IV--IV and-V.-V respectively of Fig. 1.

Referring more particularly to Figs. l and 2 of the drawings, my gear lapping machine comprises a machine base I which may comprise a pedestal portion (not shown) of any suitable conformation. On the upper face of the machine base I, a spindle head 3 is mounted in which is journallecl a shaft dior rotatably supporting any gear 'I the teeth of which-are to be lapped. A driving pulley 9 is mounted upon the other end of the shaft 5 and master driving gears I I and I3 are secured to an intermediate position thereon. As shown in Fig. 4, the lapped gear 'I is secured on the end of the shaft 5 by means of a clamping screw I5 which screws into the end of the shaft. The belt pulley 3 and the master driving gears I i and I3 are secured firmly to the shaft 5 by keys II or other suitable fastening means. The spindie head 3 may comprise a simple bearing for journalling the shaft las shown or, if preferred, the well known hermetically sealed ball bearings may be provided therein in the usual manner. A bearing I9 is mounted on a standard 2l extending from the base plate I and provides 'additional support for the shaft 5 at a point adjacent the belt pulley 9.

Lapping gears 23 and 35 are supported in operativeengagement with the teeth on the opposite sides of the lapped gear l, Aby spindle shafts 2l and 23 respectively. The. lapping gears 23 and 25 are secured by clamping` screws 3i threadably received in the shafts. The spindle shafts 21 and 23 are journalled in parallel relation in movable spindle heads 33 and 35 which are slidably supported on opposite sides of the lapped gear.

The spindle heads are mounted on sliding plates 3l and 33 andareprovided with dovetailed grooves ill in the lower surface by which they are slidably secured to cooperative dovetailed guides @i3 on the machine base i. The lateral positions of the movable spindle shafts 2l and 29 upon the machine base are independently adjusted by screw threaded shafts t5, which extend under the sliding plates 3l and 33 and which are conveniently manipulated by hand-wheels il upon the outer ends to cause the spindle heads 23 and 25 to slide laterally. The spindle heads are held firmly upon the base. I by the upstanding dovetails 43 which slide through the dovetailed grooves in the sliding plates, and by turning the hand-wheels il the distances of the spindle shafts ori opposite sides of the main shaft 5 maybe adjusted to accommodate dierent sized gears and to control the lapping operation. 4

Supported upon and adjacent to the opposite ends of the spindle shafts 2l and 23 are master driven gears 3l and 53 which are mounted for free rotation thereon and which are disposed in operative engagement with the master driving gears II and i3 respectively. The lmaster drivengears 5I and 53 tend to drive their respective spindle shafts 21 and 29 through friction driving means comprising a friction ring 55 which, as shown in Fig. 5, is rigidly secured upon the shaft by a pin 51 extending diametrically. therethrough. The surface of each friction ring 55 adjacent the associated master driven gear, is provided with a braking surface of some suitable lining material in the form of an annular collar 59 which is secured flatly against the friction ring by rivets Si or other suitable fastening means. The friction surface collar 59. may be composedv of leather, raw hide or any suitable fiberous or non-flberous material, or composition, or of a high grade brake lining material.

For continuously urging the slidable master driven gear 5| against the associated friction surface 59, a compression spring 63 is disposed concentrically upon the outer end of the shaft 21 where it reacts between the slidable driven gear 5I and an adjustable stop 65 disposed at its outermost end. As shown, the adjustable stop may comprise a nut which is threadably engaged on the end of the shaft. By turning the nut 65, the tension on the spring 63 may be adjusted to provide any desired degree of frictional engagement between the master driven gear, which is freely mounted on the shaft, and the adjacent braking surface 59 which is rigidly secured thereon. The adjustable stop nut S5 may be secured at any adjusted position by passing a Cotter pin through a suitable hole 69 in they shaft. Both of the spindle shafts 21 and 29 are driven through similar adjustable friction driving means.

As shown in Fig. 2, the spindle head 3, which supports the main. shaft 5, is mounted upon a pedestal 1l which has a groove 13 sliding over guide 15 extending across the face of the machine base I. The extended edges of the pedestal 1i are overlapped by retaining strips 11 which are secured to the machine base l by suitable screw bolts 19. By this arrangement the spindle head 3 and the main driven shaft 5 and the lapped gear 1 supported thereon may be oscillated longitudinally of the shaft to properly control the lapping action by manual adjustment or if desired, suitable means (not shown) may be pr vided for continuously oscillating the gear axially while it is being lapped, as will be readily understood.

In order to adjust the machine properly for simultaneously lapping both sides of the teeth of the lapped gear, the hand-Wheels 41 are turned for adjusting the movable spindle heads 33 and '35 to move the spindle shafts 21 and 29 laterally to suitable equidistant positions to accommodate the gear 1 which is to be lapped between the lapping gears.

For simultaneous lapping of opposite sides, the ratio of one of the master driving gears and its engaged master driven gear is selected so as to drive it faster than its associated lapping gear can rotate in mesh with the lapped gear. This lapping gear is forced, through its associated friction drive means, toward an advanced position and it laps the backsides of the lapped teeth. The ratio of the other master driving gear to its driven gear, is so selected that the latter tends to retard its associated lapping gear which then laps the front sides of the lapped teeth.

Assuming more specifically, for example, that master gears are installed upon the main shaft, having the same number of teeth as the lapped gear and the lapping gears, the master driven gears on the spindle shafts are so selected that one has more teeth and the other has less teeth than the lapping gears, which are disposed on opposite sides of the lapped gear.

With this arrangement one of the master driven gears tends to drive its spindle shaft faster and the other of the master driven gears tends to drive its spindle shaft slower than the lapped gear. The result is, as indicated diagrammatically in Fig. 3, that the teeth of the lapping gear 8| which tends to rotate faster are continuously urged into lapping engagement with the backsides of the teeth on the lapped gear 1. T'he other lapping gear 83, which tends to run slower, is constrained to continuously urge its teeth against the leading sides of the teeth on the lapped gear 1. Thus both sides of the teeth on the lapped gear 1 are lapped simultaneously by a single operation. By adjusting the tension nut 65, associated with. the frictional driving means, the lapping pressures can be ad justed to provide a predetermined lapping force which is uniform and causes the teeth of the lapped gear 1 to be uniformly processed, on both sides, by a single operation.

In accordance with my invention, my gear lapping machine may also be adjusted for lapping the teeth of the lapped gear 'l on one side only, while disposing the teeth of the respective lapping gears 23 and 25 to lap different portions thereof. This is readily accomplished by so selecting the master gears and the master driven gears that the spindle shafts 21 and 29 tend to rotate at equal speeds but at a speed diierent than the main shaft 5, which supports the lapped gear. When the backsides of the teeth are to be lapped in this manner, the gears are so selected that they tend to drive both lapping gears faster than the lapped gear 1. Then by selecting lapping gears 23 and 25, one having one more tooth and. the other having one tooth less, the teeth on the two lapping gears have different conformations such that the teeth of one lapping gear are brought into lapping engagement with the addendum surface of the teeth of the lapped gear 1. 'I'he teeth of the other lapping gear will lap the dedendum surface on the backsides v of the lapped teeth.

To lap the front sides of the teeth on the gear 1, the master driving gears and their driven gears are so selected that they tend. to drive the spindle shafts slower. By proper adjustment of the frictional driving means, different lapping pressures may be applied by the different lapping gears and the lapped teeth may be processed to any curvature desired by the operator.

Aside from the specific embodiments and adjustments of my gear lapping machine, which have been herein shown and described, it will be readily apparent that numerous details of the construction may be altered or omitted without departing from the scope of the invention as disclosed and claimed, and that I do not desire to limit the invention to the exact construction herein set forth.

VI claim as my invention:

1. A gear lapping machine comprising means for rotatably supporting lapping gears in lapping engagement with a lapped gear and driving means tending to drive respective ones of the lapping gears slower and faster than the lapped gear and including frictional means for applying a smooth continuous pressure for uniformly lapping both sides of the teeth of the lapped gear by a simultaneous operation.

2. The combination in a gear lapping machine Cil of a shaft for supporting a gear to be lapped, parallel shafts for rotatably supporting lapping gears in lapping engagement with a gear to belapped, frictional means for driving said gears, and means tending to drive one lapping gear faster and the other lapping gear slo-Wer than the lapped gear through said frietional means for applying a smooth continuous pressure tof uniformly lap both sides of the teeth of the lapped gear.

3. In a gear lapping machine the combination of a pair of lapping gears, means 'for rotatably supporting said lapping gears, a shaft for supporting a lapped gear in cooperative engagement with said lapping gears, means for driving said shaft and the lapped gear thereon, and means tending to drive said lapping gears from said shaft comp-rising speed changing means and interconnecting frictional means for applying a, smooth continuous pressure on one of said lapping gears to lap .the lapped gear teeth on one side While retarding the other lapping gear to lap the lapped gear teeth on the opposite side.

4. The combination in a gear lapping mahine of a machine base, a shaft for supporting a, gear to be lapped, bearing means for supporting said shaft on said machine base, parallel spindle shafts for' supporting lapping gears in lapping engagement with the gear to be lapped, laterally movable bearing means for supporting said spindle s hafts on opposite sides of said first mentioned shaft, means for independently adljusting said movable bearing means to vary the lateral spacing of said spindle shafts from said rst mentioned shaft, means for driving said shafts comprising speed changing means and frictional driving means tending to drive one of said spindle shafts faster than the first mentioned shaft and the other spindle shaft slower, whereby the lapping gears are driven to uniformly lap both sides of the 'teeth of the lapped gear by a simultaneous operation.

AUGUST E. THRUN. 

